Move GN obj files to target-specific dirs

build/toolchain/gcc_toolchain.gni

Index: build/toolchain/gcc_toolchain.gni
diff --git a/build/toolchain/gcc_toolchain.gni b/build/toolchain/gcc_toolchain.gni
index ae9599a461c16c4dde930746eb5861609c00ca32..31c505c40ff454831f30edcb9a48a23172930a7a 100644
--- a/build/toolchain/gcc_toolchain.gni
+++ b/build/toolchain/gcc_toolchain.gni
@@ -95,7 +95,7 @@ template("gcc_toolchain") {
       depsformat = "gcc"
       description = "CC {{output}}"
       outputs = [
-        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+        "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
       ]
     }
 
@@ -105,7 +105,7 @@ template("gcc_toolchain") {
       depsformat = "gcc"
       description = "CXX {{output}}"
       outputs = [
-        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+        "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
       ]
     }
 
@@ -116,7 +116,7 @@ template("gcc_toolchain") {
       depsformat = "gcc"
       description = "ASM {{output}}"
       outputs = [
-        "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o",
+        "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
       ]
     }